Swapping RGB LED for LED with digital controller

ZeroPhone / ZeroPhone-PCBs

PCB files for ZeroPhone - for gerbers and schematics, go to "Releases" tab!

GNU General Public License v3.0

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Swapping RGB LED for LED with digital controller #8

Open CRImier opened 7 years ago

CRImier commented 7 years ago

Currently, the RGB LED on the board is controlled by the MCP23017 GPIO expander. The expander doesn't support any kind of PWM, so right now it's only possible to show 7 colors on the LED.

Questions: Are more than 7 colors really necessary? What kind of LED could be used in place of a plain RGB LED? What kind of peripheral could be used to drive that LED?

CRImier commented 6 years ago

UPD: it seems that APA102 LED minimum communication speed will likely be compatible with the only method of digital LED driving that's currently accessible - GPIOs through userspace through I2C expander. So, I'll order some of those LEDs and do some research.

CRImier commented 6 years ago

It also seems like APA102 LEDs are 5V-only, which is bad - we only have VBAT and 3.3V in the PCB area where the RGB LED is located - doesn't look like we can somehow pull 5V there (and it doesn't make sense, either). Will see if I find some other option.